An intratracheal challenge murine model of asthma: can bronchial inflammation affect the nose?

Purified Native and Recombinant Major Alternaria alternata Allergen (Alt a 1) Induces Allergic Asthma in the Murine Model

Aeroallergens such us the spores of Alternaria alternata are described as the most important agents associated with respiratory allergies and severe asthma. Various experimental models of asthma have been developed using A. alternata extracts to study the pathogenesis of asthma, establishing the main parameters that trigger the asthmatic response. In this study, we describe a mouse model of asthma induced only by Alt a 1. To induce the allergic response, mice were challenged intranasally with the major allergen of A. alternata, Alt a 1. The presence of eosinophils in the lungs, elevated concentrations of Th2 family cytokines, lymphocyte proliferation and elevated IgE total serum levels indicated that the sensitisation and challenge with Alt a 1 induced the development of airway inflammation. Histological studies showed an eosinophilic cellular infiltrate in the lung tissue of mice instilled with Alt a 1. We demonstrate that Alt a 1 alone is capable of inducing a lung inflammatory response with an increase in IgE serum levels mimicking the allergic asthma immunoresponse when it is administered into BALB/c mice. This model will allow the evaluation of the immunoregulatory or immunotolerant capacity of several molecules that can be used in targeted immunotherapy for fungal allergic asthma.

Response of upper and lower airway inflammation to bronchial challenge with house dust mite in Chinese asthmatics: a pilot study

Background

Allergen nasal challenge can induce increase of eosinophils in sputum, but report about eosinophilic inflammation in upper airway after allergen bronchial challenge in Chinese asthmatics was rare. The article aims to evaluate response of upper and lower airways to house dust mite (HDM) allergen bronchial challenge.

Methods

HDM allergen bronchial challenge was carried out in asthmatic patients with allergic rhinitis (AR). Bronchial methacholine challenge and blood test were performed before and at 24 hours after allergen challenge. Nasal lavage and induced sputum for differential cells count and fractional exhaled nitric oxide (FeNO) measurement were performed before, 7 and 24 hours after allergen challenge.

Results

Eighteen asthmatic patients with AR underwent HDM allergen bronchial challenge with no serious adverse events reported. Fifteen patients showed dual asthmatic response (DAR), while 2 patients showed early (EAR) and 1 late asthmatic response (LAR) only. At 24 hours after allergen bronchial challenge testing, average PC₂₀FEV₁ to methacholine significantly decreased (1.58 to 0.81 mg/mL, P=0.03), while both FeNO and the percentage of eosinophils in blood and sputum were significantly increased [52.0 (54.0) to 69.0 (56.0) ppb, P=0.01; 4.82% to 6.91%, P<0.001; 20.70% to 27.86%, P=0.03, respectively], but with no significant differences found in the percentage of eosinophils in nasal lavage (39.36% to 38.58%, P=0.89). However, at 7 hours after allergen challenge, the eosinophils in sputum were significant increased to 40.45% (P<0.001), but there was an increase (39.36% to 48.07%) with no statistical difference (P=0.167) found in nasal lavage.

Conclusions

HDM allergen bronchial challenge induced different response of airway inflammation in upper and lower airways.

Inhibition of TRPA1 reduces airway inflammation and hyperresponsiveness in mice with allergic rhinitis

This study was conducted to investigate whether a transient receptor potential ankyrin 1 (TRPA1) antagonist (HC-030031) can reduce airway inflammation and hyperresponsiveness in a murine allergic rhinitis (AR) model. BALB/c mice were sensitized and challenged by ovalbumin (OVA) to induce AR. HC-030031 or vehicle was administrated to mice via intraperitoneal injection prior to OVA challenges. Nose-scratching events, histopathologic alterations of the airways, and bronchial hyperresponsiveness (BHR) were assessed. Differential cells and proinflammatory cytokines in the nasal lavage (NAL) and bronchoalveolar lavage (BAL) fluid were measured. Expressions of TRPA1 in nasal mucosa were examined by immunohistochemistry. TRPA1-expressing vagal neurons were labeled by immunofluorescent staining. HC-030031-treated AR mice had markedly reduced type-2 inflammation in nasal mucosa and ameliorated-nose-scratching events than AR mice received vehicle. HC-030031 treatment also dramatically reduced leucocyte numbers and IL-8 level in the BAL fluid, inhibited lower airway remodeling and fibrosis, and nearly abolished BHR. HC-0300031 treatment significantly inhibited the upregulated number of TRPA1 expressing nasal epithelial cells and TRPA1 expressing sensory neurons, leading to downregulation of SP in both upper and lower airways. Targeting TRPA1 may represent a promising strategy for treating AR and AR-related asthma.

Janus looks both ways: How do the upper and lower airways interact?

Our understanding of the relationship between the upper and lower airways has greatly increased as a consequence of epidemiologic and pharmacologic studies. A consistent body of scientific evidence supports the concept that rhinitis, rhinosinusitis and asthma may be the expression of a common inflammatory process, which manifests at different sites of the respiratory tract, at different times. This paradigm states that allergic reactions may begin at the local mucosa, but tend to propagate along the airway. Central to the allergic diathesis is the eosinophil and its interaction with the airway epithelium. The implications of the interplay between upper and lower airway are not only academic, but also important for diagnostic and therapeutic reasons. Furthermore, there is significant overlap in symptomatology and pathophysiology for childhood sleep disordered breathing (SDB) and asthma. Recent evidence supports an association between these two conditions, but causality has not been demonstrated. Regardless, it is important to recognize the overlap and evaluate for the other condition when one is present. In children with poorly controlled asthma, the presence of SDB may significantly contribute to asthma morbidity and, as such, should be actively excluded. On the other hand, clinical evaluation for asthma should be considered in children with SDB. Future robust longitudinal research is needed to explore the association between upper and lower airway diseases using objective measures in children.

Lung Tissue Damage Associated with Allergic Asthma in BALB/c Mice Could Be Controlled with a Single Injection of Mesenchymal Stem Cells from Human Bone Marrow up to 14 d After Transplantation

Mesenchymal stem cell (MSC) research has demonstrated the potential of these cells to modulate lung inflammatory processes and tissue repair; however, the underlying mechanisms and treatment durability remain unknown. Here, we investigated the therapeutic potential of human bone marrow-derived MSCs in the inflammatory process and pulmonary remodeling of asthmatic BALB/c mice up to 14 d after transplantation. Our study used ovalbumin to induce allergic asthma in male BALB/c mice. MSCs were injected intratracheally in the asthma groups. Bronchoalveolar lavage fluid (BALF) was collected, and cytology was performed to measure the total protein, hydrogen peroxide (H2O2), and proinflammatory (IL-5, IL-13, and IL-17A) and anti-inflammatory (IL-10) interleukin (IL) levels. The lungs were removed for the histopathological evaluation. On day zero, the eosinophil and lymphochte percentages, total protein concentrations, and IL-13 and IL-17A levels in the BALF were significantly increased in the asthma group, proving the efficacy of the experimental model of allergic asthma. On day 7, the MSC-treated group exhibited significant reductions in the eosinophil, lymphocyte, total protein, H2O2, IL-5, IL-13, and IL-17A levels in the BALF, while the IL-10 levels were significantly increased. On day 14, the total cell numbers and lymphocyte, total protein, IL-13, and IL-17A levels in the BALF in the MSC-treated group were significantly decreased. A significant decrease in airway remodeling was observed on days 7 and 14 in almost all bronchioles, which showed reduced inflammatory infiltration, collagen deposition, muscle and epithelial thickening, and mucus production. These results demonstrate that treatment with a single injection of MSCs reduces the pathophysiological events occurring in an experimental model of allergic asthma by controlling the inflammatory process up to 14 d after transplantation.

Usefulness of House Dust Mite Nasal Provocation Test in Asthma

Purpose

We previously reported that the skin prick test was sensitive and the serum specific immunoglobulin E test was specific for predicting positive airway responses to house dust mites (HDMs) in patients with asthma. Because the nose and bronchus are one airway, the nasal provocation test would be more specific for predicting the bronchial responses to HDM than the skin test.

Methods

The allergy skin prick test and nasal and bronchial provocation tests using HDM (Dermatophagoides farinae) were performed in 41 young men (age, 19–28 years) who wanted military certification for asthma. The nasal responses to HDM was scored according to the severity of rhinorrhea, sneezing, and nose itching.

Results

The prevalence of a positive skin prick test to HDM did not significantly differ between patients with (n=24) and without (n=17) an early airway reaction (EAR; 79.2% vs 70.6%, P=0.534). However, the prevalence of a positive nasal test was significantly higher in the airway responders than in the others (37.5% vs 0%, P=0.005). The concordance of a positive response to the nasal test (κ=0.332, P=0.004) but not to the skin prick test (κ=0.091, P=0.529) was significant with an EAR. The diagnostic sensitivity of the nasal test (37.5%) was lower than that of the skin prick test (79.2%), but the specificity was higher (100% vs 29.4%).

Conclusions

The skin prick test is more sensitive, whereas the nasal test is more specific and accurate, for predicting an EAR to HDM in patients with asthma.

United airway disease: current perspectives

Upper and lower airways are considered a unified morphological and functional unit, and the connection existing between them has been observed for many years, both in health and in disease. There is strong epidemiologic, pathophysiologic, and clinical evidence supporting an integrated view of rhinitis and asthma: united airway disease in the present review. The term “united airway disease” is opportune, because rhinitis and asthma are chronic inflammatory diseases of the upper and lower airways, which can be induced by allergic or nonallergic reproducible mechanisms, and present several phenotypes. Management of rhinitis and asthma must be jointly carried out, leading to better control of both diseases, and the lessons of the Allergic Rhinitis and Its Impact on Asthma initiative cannot be forgotten.